Improvement Of The Spinosyns-producing Strain By Rational Screening And The Optimization Of Its Fermentation Process

The discovery and characterization of the soil actinomycete Saccharopolyspora spinosa represented a novel opportunity to develop a portfolio of progressive insect management tools. The favorable mammalian and environmental profile, insect selectivity, unique mode of action and outstanding efficacy are resulting in rapid registrations and adoption by farmers around the world. In this paper, the determination of spinosyns by HPLC, the strain improvement by rational selection and the optimization of the spinosyns fermentation process were studied.Analyzing method of spinosyns by HPLC was introduced. The result shows that the relative standard deviation, the coefficients of variation; the linear correlation and the average recovery were 0.11%, 0.15%, 0.99916, and 96.94% respectively.Based on the biosynthetic pathway and metabolic regulation of S. spinosa., a rational selection procedure was performed to obtain a higher spinosyns-producing strain. The higher productive strain S. spinosa 4-6 was selected, which, after UV mutation, could grow well on the medium with corresponding concentration of spinosyns, rhamnose and 2-deoxygen-D-glucose (2-DOG). The productivity reached 268mg/l, which was 121% more than that of the parent strain S. spinosa 1-5.The optimization of the fermentation progress was studied. The effects of carbon sources, nitrogen sources, inorganic salts, precursors, pH on spinosyns fermentation were studied in the shaking flasks. The plate medium, slant medium and seed medium were optimized systematically. A set of cultural medias and conditions to make the strain grow better and get higher productivity was obtained.Based on the results in shaking flasks' fermentation, spinosyns fermentation was scaled up in a 10L fermentor, and a productivity of 458mg/l was obtained, which was 71% higher than that in the shaking flasks.